Catalysts are well known to be useful in certain reactions. In particular they can be used to promote particular reactions which would not normally take place in the absence of the catalyst.
An example of a reaction where a catalyst is useful is the production of syngas, which is a mixture of carbon monoxide and hydrogen in varying proportions. It is known to produce syngas by a steam reforming reaction wherein steam and methane are passed over a catalyst. Such a reaction is endothermic.
Recently syngas has also been produced by the partial oxidation of methane (POM). In this process methane is partially oxidised with oxygen in the following reaction:CH4+1/202→CO+2H2 
The POM reaction has the great advantage of being exothermic, and hence does not require a great energy input. The process is described in further detail, for example, in Choudhary et al, Fuel, vol. 77, No. 15, pp 1803–1807, 1998, Slagtern et al, Catalysis Today, 46, 107–115, 1998 and WO 01/36,323. In a modification of this process, other hydrocarbons may be used as well as or instead of the methane. As used in this specification, the term “POM” is intended to cover not only the partial oxidation of methane but also the partial oxidation of any hydrocarbon.
The POM reaction generally uses a nickel or cobalt containing catalyst or a noble metal catalyst. For example Choudhary et al discloses the use of various such catalysts. For example, a cobalt containing catalyst can be prepared by mixing cobalt nitrate with a support such as silica gel and deionised water to form a thick paste, mixing the paste and drying and decomposing the paste in air at 600° C. for 4 hours before calcining the catalyst at 900° C. for 4 hours. This reference also indicates that the catalysts may be reduced using hydrogen before they are used, but that the performance of reduced and unreduced catalysts is comparable. It has also found that the best catalysts are nickel-containing catalysts such as NiO—Tho2, Ni—ZrO2 and Ni—UO2. 
Another example of a process where a catalyst is useful is in a Fisher Tropsch synthesis reaction in which a mixture of hydrocarbons is produced from carbon monoxide and H2.